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Classifications

• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L61/00—Network arrangements, protocols or services for addressing or naming
  • H04L61/59—Network arrangements, protocols or services for addressing or naming using proxies for addressing
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L61/00—Network arrangements, protocols or services for addressing or naming
  • H04L61/50—Address allocation
  • H04L61/5007—Internet protocol [IP] addresses
  • H04L61/5014—Internet protocol [IP] addresses using dynamic host configuration protocol [DHCP] or bootstrap protocol [BOOTP]
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L41/00—Arrangements for maintenance, administration or management of data switching networks, e.g. of packet switching networks
  • H04L41/50—Network service management, e.g. ensuring proper service fulfilment according to agreements
  • H04L41/5041—Network service management, e.g. ensuring proper service fulfilment according to agreements characterised by the time relationship between creation and deployment of a service
  • H04L41/5054—Automatic deployment of services triggered by the service manager, e.g. service implementation by automatic configuration of network components

Definitions

• This invention relates to the configuration of network elements such as routers to effectively handle requests for IP addresses using Dynamic Host Configuration Protocal (DHCP).
• DHCP Dynamic Host Configuration Protocal
• FIG. 1 shows a generic description of a broadband network for providing telephone, internet and TV/video services to subscribers in a number of locations.
• a series of service providers provide the various services (SP 1 , SP 2 , SP 3 ) to the network 10 via conventional access points 12 .
• the network 10 provides connection to these subscribers via routers 14 located close to the subscribers.
• the subscribers can include business locations that can include routers in commercial property 16 , and domestic subscribers with routers located in a central office 18 for a neighbourhood of separate dwellings (houses 17 ), or in a single building 19 such as an apartment.
• a network operator manages the network function by the use of a control and provisioning system 20 .
• the present invention is particularly applicable to such networks.
• the network can be considered in an abstract way as comprising a core 22 having one or more cells 24 , each cell having one or more network elements 26 as is shown in FIG. 2 .
• Subscribers 28 connect to the network elements 26 .
• the functional blocks 22 , 24 , 26 may be wholly or partly resident in the same or different physical elements, depending on the exact size and makeup of the network in question, although typically, each network element 26 will comprise a router.
• the subscribers (network clients) can comprises a PC or other connected network device.
• the Dynamic Host Configuration Protocol is a set of rules used by communications devices to allow the device to request and obtain an IP address (and other parameters such as the default gateway, subnet mask, and IP addresses of DNS servers) from a server which has a list of addresses available for assignment.
• the DHCP server ensures that all IP addresses are unique, e.g., no IP address is assigned to a second client while the first client's assignment is valid (i.e. its ‘lease’ has not expired).
• IP address pool management is done by the server and not by a human network administrator.
• the procedure by which an IP address is obtained from a DHCP server is shown schematically in FIG. 3 .
• the router R can be configured in the factory (as is the case in many home routers) or can be manually configured by either downloading a configuration file or by connecting to the router by telnet and configuring the code operating the router. Whichever way is used, the configuration is essentially static and includes identification of the DHCP server extDHCP to use for IP address assignment.
• the client C requests an IP address by sending a DHCP discover message (i) to the router R.
• the router R relays it on to the network, including the DHCP server extDHCP (ii).
• the DHCP server responds to this message by issuing a DHCP offer (indicating that an IP address is available to meet the request) which is communicated to the router R (iii) and is in turn, relayed to the client C (iv).
• the client issues a DHCP request to the router R (v) which in turn is relayed to the network (and DHCP server) (vi).
• the DHCP server assigns a particular IP address and issues an acknowledgement, including the assigned IP address (vii) which in turn is relayed by the router R to the client (viii). Steps v to viii are repeated periodically to maintain the lease to that IP address while the client is connected. In the event that the client disconnects (or is timed out), the IP address is released and steps i to viii must be repeated again to obtain a new IP address.
• the static configuration of the router makes it difficult for the network to adapt to the changing needs of the clients.
• the method preferably further comprises analysing the request from the client to determine a service type to which the request relates and creating a configuration instruction according to the determined service type.
• the step of obtaining a configuration instruction can comprise creating the configuration instruction in the router from one of a number of configuration templates according to the service type.
• the method comprises analysing the request from the client to determine a service type to which the request relates; sending a message from the router to the control system to request a configuration for DHCP services according to the determined service type; and sending a configuration instruction from the control system to the router.
• the configuration instruction can comprise an instruction including an IP address pool from which the router can assign an address to the client when acting as a DHCP server or an instruction including the identity of the external DHCP server to which the IP address request is relayed.
• the method can comprise sending relay agent information with the request to the external DHCP server.
• the external DHCP server may be identified.
• the router When the router is configured to act as a relay agent, the router may send an update message to the control system when forwarding the IP address from the external DHCP server to the client.
• a network system comprisings a number of routers, a number of network clients, and a network control system, wherein each network client connects to a network via an associated router and the router is under the control of the control system, the control system being configured so as to perform the steps of the method in accordance to the first aspect of the invention.
• the system may further comprise at least one external DHCP server.
• FIG. 1 shows a schematic view of a generic broadband network
• FIG. 2 shows a schematic view of the functional elements of a network
• FIG. 3 shows the major steps in DHCP IP address assignment
• FIG. 4 shows a system according to an embodiment of the invention with a router configured to act as a DHPC server;
• FIG. 5 shows a system according to an embodiment of the invention with a router configured to act as a relay agent with an external DHPC server.
• the router R acts as the DHCP server and provides the IP address.
• the router R sends out a DHCP discover 1 as before.
• the router R sends a context open message 2 to the control system CS.
• This provides information such as the interface ID on the router R, MAC address, vendor class ID for the service concerned, etc.
• the control system creates a configuration file establishing service parameters for the requested service (bandwidth, etc) as well as an IP address pool from which at IP address can be assigned.
• the configuration file (instruction) is transmitted to the router R in a context write, step 3 .
• the configuration file is loaded into the router R which then begins to behave as a DHCP server and sends a DHCP offer on the specified interface to the client C.
• the steps of DHCP request and acknowledge outlined above are completed between the client C and router R, via steps 5 , 6 (repeated in the usual manner to maintain the lease open).
• the router R acts as a DHCP server for the device connected to the designated interface.
• the router acts as a DHCP server for all devices attached to an interface.
• FIG. 5 shows the system configuration for this case.
• the DHCP discover and context open steps 1 , 2 are as before. However, in this case, the control system responds with the identity of the external DHCP (extDHCP) sever to use, step 3 and the router R is configured accordingly. Although only one server is shown, it is possible that more than one can be specified according to the service requested.
• the router R relays the DHCP discover to the designated server and includes “option 82” (relay agent) information if not already present, step 3 a .
• the DHCP server responds with a DHCP offer, step 3 b . This is relayed to the client C, step 4 .
• the client C then responds with a DHCP request, step 5 as before. This is relayed by the router R to the DHCP server 5 a .
• the server responds with a DHCP acknowledgement, step 5 b which is relayed to the client C by the router R, step 6 .
• the router also sends a context update, step 7 to the control system CS so that the address and service assignment to the client C on the relevant interface can be known to the control system. Steps 5 , 5 a , 5 b and 6 are repeated to maintain the IP address lease open as needed.
• the system is configured as in FIG. 4 or FIG. 5 is irrelevant; it is provided with an IP address and responses received from the router R are in the same format in both cases.
• the router R is configured according to the interface on which the request is received, it is possible to have several different configurations provided by the router R. For example, certain requests may be handled in the manner of FIG. 4 , i.e. with the router R acting as the DHCP server, whereas others are handled in the manner of FIG. 5 , with the router acting as a relay agent and using an external DHCP server to provide the IP addresses.
• IP address lease At the end of an IP address lease, the address is released and the client loses its IP connection.
• the next DHCP discover from that client on that interface will be treated as new and may be handled in a different way to the way in which it was previously.
• the dynamic nature of the router configuration means that it is relatively easy to control the system to adapt to new services or providers, and does not require manual re-configuration of each router. This avoids the need to manually reconfigure every router once a new server or service is added to the system.
• some control system functionality is provided in the router R.
• the control system may inspect the clients' DHCP discover message, in particular fields containing the client MAC address and the vendor-id field which are used to determine what type of client service causes the request for the IP address.
• Moving this functionality to the router R involves providing a set of service templates in the router R.
• the router R inspects the DHCP discover message and attempts to match it against templates in a service list of client conditions. If a match is found in the list, that means that the particular service can be provided to the client.
• the service template can in turn also indicate that the packet should be relayed to an external DHCP server, the router's own internal DHCP server used, or a query sent to the control system for additional configuration information for the client.
• This approach has the advantage that it provides a way to avoid the control system from the signalling chain, thus reducing the potential for every IP address assignment to be a possible single-point-of-failure.
• This general process would comprise analysing the message from the client to determine the service type, and then either configuring the router according to a stored template to either act as the DHCP server or to relay the request to an external DHCP server, or to pass the message on to the control system and respond in the same manner as is discussed above.

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• Engineering & Computer Science (AREA)
• Computer Networks & Wireless Communication (AREA)
• Signal Processing (AREA)
• Small-Scale Networks (AREA)
• Data Exchanges In Wide-Area Networks (AREA)

Abstract

Description

Claims (18)

Applications Claiming Priority (4)

Publications (2)

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ID=39049014

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Cited By (1)

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Citations (113)

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• 2007
  • 2007-10-12 DE DE602007005946T patent/DE602007005946D1/en active Active
  • 2007-10-12 AT AT07118409T patent/ATE464733T1/en not_active IP Right Cessation
  • 2007-10-12 EP EP07118409A patent/EP2048858B1/en not_active Not-in-force
• 2008
  • 2008-10-03 WO PCT/EP2008/063270 patent/WO2009047215A1/en active Application Filing
  • 2008-10-03 US US12/682,360 patent/US8543674B2/en active Active

Patent Citations (118)

Non-Patent Citations (15)

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